Monday, September 26, 2011

A new toy

I picked up a Ceramic Folding Knife on the internet. $49 + $5 postage - from Canada to Ireland. Nice, usually postage makes things like that prohibitively expensive.

You can see them at

It's about as sharp as you will make a steel knife without taking a strop to it. That is it slices paper like all the demos you see on youtube, it won't shave the hair off the back of your arm, but, it will slice through 8mm poly double braid without any fuss at all. (Which is more important than shaving your arm bald!)

The handle is stainless, the blade is ceramic. It's held together with tiny recessed bolts, so you can take the whole thing apart if you even need to. (Not that there's anything to go wrong).

It clicks closed, so it won't pop open accidentally. And it locks open.

It feels light, but not in any way flimsy. It takes a little practice to pop it open without your thumb getting too close to the blade, it sort of pops, and your thumb can slip of the stud. The blade is only an inch wide, if the back of the blade was a bit wider, there'd be more room for the thumb stud.

On the whole a very nice toy. I can't help thinking my modified Myrchin will still be my go too knife on the boat, 'cause I know it's bullet proof. But I suspect that this one will have it's place too. I just want to see how resilient it is.

But on the whole nice toy.

Sunday, September 25, 2011

Cutting Rope

I have a Myrchin P300 knife. It's really quite nice. But the serrations are very aggressive.
This means that

  1. It catches in the rope if you try to cut rope.
  2. I can't sharpen it very well (ymmv)
  3. At the end of it all, I take 3 serious attempts to cut 8mm double braid.
I have a small Leatherman and it has a plain blade and a serrated blade.  The plain blade will take an edge which cuts through 8mm double braid like it was wet tissue. The serrated blade, having shallow scallops, does the same, and is easy to sharpen. But it's fiddly to open, needing two warm dry hands.

So I got out my coarse diamond stones, and ground down the serrations on the Myrchin until they were less like a comb! Then I sharpened it (with a spyderco sharpmaker), and just because I could, I honed the blade on a cheapo cloth wheel powered by a drill with some polishing compound.

My Myrchin now cuts through the 8mm poly with callous disregarding ease. It sits nicely in my pocket, it has a pliers, and a locking marlin spike. And now it has the blade that I'd have put on it. It does not look nearly as scary as the original blade. But when your hands are cold, you are tired, and something is tangled, if you want to "untangle" it, you don't care much for how scary the blade looks.

Monday, September 19, 2011

Well that didn't suck !

The wooden pump sucks water just fine, provided that it's either in water, or primed. It won't self prime more than about 3" or so. I could see the water climb about 3" through the clear plastic hose. No More.

I guess that while the clearance of the piston, and the valves was just fine for water, air just flows past them. I could do a better job, and add seals, and improve the valves, but now the engineering is starting to get to the stage where it's very time consuming, and fragile.

So, I'm just glad that I only made a mock-up, and did not spend a lot of time making it pretty.

Oh well.

Some you win.

Monday, September 12, 2011

A wooden Pump

I can't claim credit for this, I found it here at duckworks (thanks By Tim Ingersoll - Superior, Wisconsin - USAbut I thought it would look a lot better on my boat than a grey / black plastic thingy.

I cobbled one together out of scrap plywood to see if it simply functioned. I didn't want to spend a lot of time and effort and expensive wood to find out that it trickled water out, or had to be made to perfect tolerances.

It was easy to make, it moves LOTS of water with very little effort. It does splash water out the top where the handle comes out, so I need to try to make a "seal" there with rubber.

I need to try it with a pipe out the bottom to see how well it primes, but I think I will be putting my whale gusher urchin up on ebay shortly.

If it will self prime well enough, I see one each side of the boat, with a pipe to the other side, so that I can pump out the boat while I'm on the windward side.

Photos and test results for self priming to follow. But I've a Math project to hand up, so it may be a little while.